Sample types and analytical techniques.

Sample types and analytical techniques.

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The research presented in this paper focused on the preliminary non- and semi-destructive analysis of copper alloys, corrosion, and soil components from a Roman archaeological site in Israel. Investigations using portable X-ray fluorescence, X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy as well as micromorph...

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Context 1
... overview of the sample types, analytical techniques and the expected information can be found in Table 1. ...

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... In the paper entitled "Roman coins at the edge of the Negev: characterisation of copper alloy artefacts and soil from Rakafot 54 (Beer Sheva, Israel)" [3] Manuel J. H. Peters and co-authors report about the preliminary non-and semi-destructive analysis of copper alloys, corrosion products, and soil components from a Roman archaeological site in Israel. The use of a multianalytical approach based on X-ray fluorescence, X-ray diffraction, scanning electron microscopy, and micromorphological analyses allowed the researchers to characterise the corrosion products and to correlate them to the soil composition. ...
... A preliminary study by Peters et al. [28] analysed the chemical composition of the artefacts under investigation by means of Xray fluorescence. This study revealed that most of the artefacts were produced from a copper-lead-tin alloy, with a lead content that, in some cases, reached 14 wt%. ...
... Moreover, despite the preliminary cleaning, soil traces caused a broad fluorescence signal in the central part of the spectrum, between 1,200 cm −1 and 3,000 cm −1 , as can be seen in Figure 2 for sample 9883. A good signal-to-noise ratio could be obtained only when brightgreen patinas were analysed, while measurements could not be performed on the brownish patinas, possibly associated with cuprite [28]. This could be due to the low thickness of these layers or to the excitation wavelength that was used in this study; only a 532 nm laser light was employed. ...
... Thus, it is possible to state that the corrosion patina of the artefacts under study is mainly composed of copper hydroxychlorides, specifically atacamite and clinoatacamite. This agrees with the preliminary studies, which indicated the presence of chlorides in the excavation soil [28]. The presence of only two kinds of corrosion product suggests the existence of quite uniform conditions in the soil where the artefacts were buried, although, as discussed above, performing Raman spectroscopy with a different laser wavelength might reveal other compounds. ...
Article
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This paper illustrates a case study related to the characterisation of corrosion products present on recently excavated artefacts. The archaeological findings, from the Rakafot 54 site (Beer-Sheva, Israel), consist of 23 coins and a pendant, all dating back to the Roman period. Raman spectroscopy was used to identify the corrosion products that compose the patina covering the objects. To facilitate and support their identification, spectra were then processed using principal components analysis. This chemometric technique allowed the identification of two main compounds, classified as atacamite and clinoatacamite, which formed the main components of the patinas. The results of this investigation can help in assessing the conservation state of artefacts and defining the correct restoration strategy.